1. Field of the Invention
The present invention relates to an ink jet cartridge in use for ink providing jet function, an ink jet cartridge, to an ink jet and also a method therefor, which are applicable for devices including copying machines, recording apparatus such as facsimile devices, telecommunication instruments, composite instruments thereof, and printers.
2. Brief Description of the Related Art
An ink jet cartridge in use for an ink jet device is normally integrally formed with an ink jet head. In most cases, such a conventional cartridge is replaced together with the used head, when the cartridge is reached the step at which the ink will not be injected. A comparatively large amount of ink is still remaining in the cartridge, because of being governed by ink retention ability of sponge material which is contained in the cartridge.
In a cartridge of the above type, such as disclosed in Japanese laid-open patent publication No. 63-87242 a foam material is enclosed in the cartridge, which is integral with an ink jet recording head furnished with a plurality of ink injecting orifices. As ink is contained in foam material such as polyurethane foam, a negative pressure produced by capillarity of the foam achieves conservation of the ink (i.e. prevention of ink leakage out of the container). However, as the foam must be filled over almost entirely within the ink chamber, the filling quantity of ink is not only restricted, but also the amount of ink remaining unused in the foam will increase. As a result, there are needed several improvements in filling effect and efficient use of the ink material. Also, problems still remain in difficulty of detection of remaining ink and possibility of ununiformity of injecting property of ink.
Another prior art discloses an ink jet cartridge containing substantially solely an ink material. Japanese laid-open patent publication No. 2-522 discloses an ink jet head having an integral construction in which a few amount of porous material is provided between an upper positioned primary storage section in which a large amount of ink is contained and a lower positioned ink jet head. According to the description, an advantage is mentioned that, because the porous material is not enclosed in the ink storage section but disposed only in an ink passage, the using efficiency of ink is increased. Another advantage is also mentioned that it is possible to tentatively store the ink flown out of the primary ink storage section due to temperature rise of the enclosed air (and pressure decrease thereby) by providing a secondary ink storage section in the side of the porous material, and thus to maintain the negative pressure applied on the head at the recording step at substantially a constant value.
However, in the invention therein, the production of negative pressure is almost reduced, because the porous material is present in the ink passage, and an over sufficient amount of ink is soaked in the porous material with the ink supplied from the primary ink storage section which is upwardly positioned and stores a large amount of ink. Accordingly, there has been possibility of flowing out of ink from the orifice of the head, even applied with a slight shock. Also, it is not adequate in practice to form the above mentioned type of the ink container as a replaceable type of ink jet cartridge detachable with the ink jet head. The reason therefor is that there is possibility of flowing out of the ink from the head-ink jet cartridge joint portion into the ink container, since the negative pressure is generally diminished.
Another ink jet cartridge is also known, in which the ink is enclosed in a bag and a spring member is additionally provided to control the deformation of the bag for maintaining the negative pressure of the porous material itself in a predetermined value. But the cost thereof was increased and also it was impossible to maintain the structure of the spring to achieve a mass production of devices.
In any cases, any ink jet cartridge for ink jet purpose (that is, non-contact type printing use) manufactured in low cost but provided with a reasonable technical level is not still produced.
In an ink jet recording method using a piezoelectric element, recording is performed by injecting ink by use of a drive voltage not less than 40 V in the on-demand mode or continuous mode. The element is in usual driven by a driving voltage required to correctly inject the ink in spite of any environmental change. An embodiment thereof is disclosed in Japanese patent publication No. 58-6752.It is also disclosed therein a various colored ink containing an amount of 0.0001 to 10 weight % of an ethylene oxide addition product. It is evaluated therein that an ink containing a surface active agent, that is surfactant, is excellent in fixing property and water resistance in comparison with that without surfactant. It is further disclosed therein that it is possible to determine if the ink can be injected by checking the first drive signal obtained after being kept for three months, and that the ink containing a surfactant can perform an excellent ink injection.
In this connection, in "Shin Kaimenkasseizai Nyumon" (A New Guide Book of Surfactant, revised edition) published on Oct. 1, 1981, it is disclosed that it is quite a natural knowledge to mix a surfactant of an amount of exceeding the critical micelle concentration (abbreviated as "c.m.c.") into the liquid when such a surfactant is to be contained into a liquid in order to obtain a sufficient effect of adding the surfactant. Also, there are two U.S. Pat. Nos. 5,106,416 and 5,116,409, each discloses an invention featured in that a surfactant of an amount of exceeding the critical micelle concentration is mixed with an ink material. In these specifications, the effect for preventing bleeding of the ink is disclosed, and no meaning of the critical micelle concentration of a surfactant when mixed into water. In contrast, Japanese laid-open patent publication No. 56-49771 discloses an ink material containing a surfactant of not exceeding the critical micelle concentration, and also is mentioned therein such an ink can produce an effect of preventing blinding which occurs in the nozzle. Also, similar to Japanese patent publication No. 58-6752 mentioned above, there is Japanese laid-open patent publication No. 1-182384 (1989), which discloses an invention on an ink to enable the use of an ink containing 1 to 10% of a surfactant by admixing a solvent of low vapor pressure and low viscosity. But it is merely considered therein bleeding of the ink with the paper to be printed thereon.
In any case, there has been no invention which precisely discloses the stability of behavior throughout the course ranging from the ink chamber or ink jet head until the behavior of the ink drops after injected out of the ink jet head, and the relationship between the ink chamber and the ink itself for making sure of improving the printing quality, which is considered over the range which sufficiently covers until the course of the injection behavior of the ink jet head.
In either the proposed replaceable ink cartridge or the structure of the ink container disclosed in Japanese laid-open patent publication No. 63-87242, firstly, no attention is paid as to the structural change of ink drops produced from the ink jet head: and secondly, no attention is paid as to the correlation between the phase conversion of the ink contained in the ink jet head; production of minute ink drops, called satellite dots or microdots, which are separated from the normal drops while they are flowing and produced; and the behavior of the ink against the recording medium. Accordingly, any of no reasonable solutions relating to ink property or recording method for ensuring recording properties is provided.
As another technical field using the ink material, there is contact recording technique, in which generally the ink is supplied to the recording core having capability of ink absorption and preservation.
As an example of ink feeding in contact recording technique, it is mentioned the laid-open utility model publication No. 57-16385, in which is disclosed a recording pen for a recording instrument using a recording core, that is, a porous ink absorbing core.
The invention disclosed therein is a structure which comprises a central section including a recording core, a first cotton-like fiber engaging with the recording core, a second cotton-like fiber absorbing a small amount of ink at the opening in communication with the atmosphere but allowing less passage of ink compared with the first cotton-like fiber; and a tightly sealed ink chamber section capable of feeding through the passages provided on the opposite sides of the central section.
In operation therein, the air contained in the ink chamber section is expanded due to temperature rise of the ambient temperature to allow the ink to flow into the first cotton-like fiber. Then, the ink of the amount exceeding that possible to be soaked is absorbed by the second fiber to prevent the ink from being overflown and dropped out of the recording core.
Also disclosed therein is provision of a groove having a predetermined width for permitting the expanded air to escape toward the air passage, when one of the two ink chambers is filled with air only. Such a groove is formed in the range from the lowermost end to the uppermost end of the side surface different from the partition of the central section and the tightly sealed section.
However, in the recording pen of the non-contact type recording instrument, no attention is paid for a stable negative pressure production for preventing ink leakage out of the recording assembly, especially in the field of non-contact type ink jet recording technology.
Further, it is pointed out that the ink consumption from the ink chambers of the both sides does not always occur in the same amount to each other, and rather the ink from either one chamber is likely to be in advance consumed. Although there is paid attention on leakage from the recording core in accordance with various environmental changes, there is still possibility of further problems which would occur in the field of ink jet recording, such as disconnection of the ink passage way or invasion of air bubbles into the recording assembly.
In order to solve the above problems, the same inventors proposed an improved ink jet cartridge for the ink jet device, which is featured in provided with two advantages, that is, an excellent feeding of ink material of an amount corresponding to the amount of ink ejected from the recording head during printing operation, and there is no drawback of ink leakage from the outlet during non-printing, and these were disclosed in Japanese patent application Nos. 4-198474 and 4-198681 of the same inventors.
Based on the discussion above, it has been found that the construction which is effective for making best use of ink jet characteristics is comprised of, as the fundamental construction, a first ink chamber and a second ink chamber: the first chamber for receiving a negative pressure producing material, provided with an air communication passage for achieving air communication with the atmosphere, and serving as the container for the negative pressure producing material; and the second chamber being an ink chamber, which is in communication with the first chamber but is substantially in tightly sealed condition, for directly and tentatively accommodating the ink material which is to be supplied into the first chamber.
According to the above construction, a structure of an ink chamber, by which the negative pressure is maintained at a substantially fixed value throughout almost all the period ranging from the initial use to final use of the ink jet cartridge, is obtained, and accordingly, the present invention can provide a replaceable ink jet cartridge and a ink jet head as well as a printer, which are in response to the high speed recording.